Stuttering that continues into adolescence and adulthood is often accom- panied by negative personal and social consequences that can influence school performance, choice of profession, and chances of promotion. If effective treatment can be provided for children in preschool and primary school, most adult stuttering (40% 80%) can be prevented. Large , meaningful studies that can define the efficacy and efficiency of stuttering therapy in young children need high priority in communicative disorders research. It is also important to identify factors that might improve the choice of therapies for this population. A recent, major review of systematic, behavioral therapies for stuttering cited 20 studies with a combined N of 36 children ages 3-12. Only four children ages 3-5 and 10 children ages 6-8 have been studied. These 14 children provide a meager data base for therapy decisions. The proposed project plans to evaluate the efficacy of favored and repli- cable therapies using 60 children ages 3-9 of whom 40 stutter. Two therapy approaches, using 20 stutterers each, will be systematically compared. A group of 20-nonstutterers will serve as controls.. A review of therapies that have promise in treating stutterers in this age group highlights two important and different therapy approaches. The first, designed to reduce stuttering by improving speech motor skills, has been reported in studies that serve as pilots for the proposed project. The second, which has emerged as the best combination of experimentally tested behaviorally based therapy, is known as Extended Length of Utterance. These two approaches will be compared using subjects from two age levels (preschool and primary school) who display a range of speech performance and speech motor skills. The design will determine whether these variables predict efficacy and efficiency of the studied therapies. NIH has recently recognized the urgent need to study therapy for young stutterers. They called for investigations which address spontaneous remission, early intervention, stuttering reduction during therapy, and maintenance of therapy gains. All of these issues are included in the proposed design. Also, the design identifies the effects of age and level of speech motor skills on therapy outcome.